Currently, photosensitive resin compositions are widely used in various semiconductors and in microfabrication. In these applications, the photosensitive resin composition on a substrate is exposed to active rays and subjected to a proper treatment with a developer for selective removal of exposed portions or unexposed portions so as to form a resist pattern. During the treatment, optical processing is achieved by inducing changes in solubility of the photosensitive resin composition. The photosensitive resin composition may be either one of a positive type or a negative type, and the exposure with active rays is performed to increase or decrease the solubility in the developer, depending on the use.
Conventionally, materials including a combination of an acrylic photo-curing agent and an epoxy heat-curing agent have been used as the material system. For example, a photosensitive resin composition containing a novolac resin, an epoxy resin, and a photo-acid generator is disclosed in Patent Literatures 1 and 3, and a photosensitive resin composition containing an alkali-soluble epoxy compound having a carboxyl group and a photo-cationic polymerization initiator is disclosed in Patent Literature 4. Further, a photosensitive resin composition relating to a surface protective film or an interlayer insulating film of a semiconductor is described in Patent Literature 2.